vsock: query features supported by vhost vsock driver
vsock: query features supported by vhost vsock driver

Query fetures supported by vhost vsock driver instead of hardcoding
supported features. It may help to avoid compatible issues when
supporting multiple linux kernel versions.

Signed-off-by: Liu Jiang <aaf6961e30ae80fd3a577c4cb6742ab6a1ad13eb@linux.alibaba.com>

firecracker-microvm/firecracker,firecracker-microvm/firecracker,firecracker-microvm/firecracker,firecracker-microvm/firecracker,firecracker-microvm/firecracker